X-ray lithographic mask using rare earth and transition element compounds and method of fabrication thereof

Abstract

There is described a unique mask and method of making same. The mask is especially useful in high resolution fabrication techniques such as in making magnetic bubble domain structures, semiconductor device structures and the like. The mask includes a suitable support of appropriate density to be substantially transparent to various types of radiation such as, but not limited to, E-beams, X-rays and the like. A layer of material which is substantially opaque to the same radiation and which can have the solubility thereof changed by application of E-beams or the like is provided on the support material. The mask is exposed to the solubility changing radiation wherein a pattern is defined in the layer, the layer is etched in a non-critical etch so that the soluble portion thereof is removed and the remaining material provides a suitable pattern. To the extent necessary, a suitable auxiliary support member can be provided to the support.

Having thus described a preferred embodiment of the instant invention, what is claimed is: 
     
       1. A high resolution mask formed by the steps of; providing a substrate which is substantially transparent to x-ray radiation,   disposing a layer of masking material on a surface of said substrate which masking material is substantially opaque to x-ray radiation,   said masking material is selected from the class comprising rare earth compounds, rare earth oxides, mixed rare earth oxides, and transition element compounds,   directly exposing portions of said layer to E-beam radiation to alter the solubility of the exposed portions of the said layer, and   applying a solvent to said layer to remove parts thereof which are readily soluble in said solvent thereby to establish a pattern of said layer on said substrate.   
     
     
       2. The mask recited in claim 1 wherein, said layer of masking material is less than about 5000 A thick.   
     
     
       3. The mask recited in claim 1 including the step of providing an auxiliary support means for said substrate. 
     
     
       4. The mask recited in claim 1 wherein said patterned layer comprises oxides of tungsten, molybdenum, tantalum, niobium, and europium individually or in combination.